This invention relates to a novel and improved method of producing a packed food and an apparatus for carrying out such method.
In recent years, there have been developed methods and apparatus for producing packed foods wherein a charge of a predetermined volume of unprocessed foodstuff is simply filled in a heat resistant packing film and positively ripened and sterilized by heat generated by an electric current passed therethrough, to readily provide precessed foods packed with the film to enable the foodstuff to be handled hygienically.
A proposal has been made by us to provide a method of producing a packed food which is disclosed in Japanese patent publication No. 48789/80. In this method, unprocessed foodstuff is placed in a packing bag formed at upper and lower surfaces with a multiplicity of minuscule current passing apertures and packed therein to provide a packed foodstuff. A pair of electrode plates are each placed against one of opposite surfaces of the packed foodstuff through a salt solution impregnated electrical contact member, and a current is passed between the two electrode plates while forming the packed foodstuff into a desired flat shape, to ripen and sterilize the foodstuff by the heat generated by electricity. Thus the packed foodstuff is processed into a processed packed food.
In the aforesaid method, the packing bag used for containing the unprocessed foodstuff is formed of heat resisting and insulating material which is soft and pliable and open at opposite ends. When a charge of foodstuff is filled in the bag, it is necessary that one open end of the bag be first tied up or otherwise closed and then the desired foodstuff be filled in the bag through the other open end, the other open end being sealed after the foodstuff is filled in the bag. This packing operation is troublesome and time-consuming. When a large number of packed foods are to be produced, it is impossible to carry out the operation efficiently in a short period of time. In addition, the packing bag is very thin and soft, and the open ends thereof become sticky when wet by the foodstuff charging operation, thereby making it difficult to readily open the ends. When such situation occurs, difficulty is experienced in filling the packing bag with a charge of unprocessed foodstuff in a predetermined volume, thereby making it difficult to perform foodstuff charging efficiently. In other words, the method has been found to be unsuitable for mass production of packed foods.
This invention has been developed for the purpose of obviating the aforesaid problem of the prior art. Accordingly, an object of the invention is to provide a method of producing a packed food using a packing film in the form of a sheet of film formed with a multiplicity of current passing apertures, wherein the packing film is forced into an insulating container open at opposite ends in such a manner that the minuscule current passing apertures are located in a horizontal plane, and a charge of unprocessed foodstuff is filled in a predetermined volume in the packing film thus forced into the insulating container. In this way, the foodstuff can be readily and quickly filled in a package to provide a packed processed food by merely passing a current uniformly through the foodstuff, no matter what the shape of the foodstuff may be.
Another object is to provide an apparatus for producing a packed food, in which unprocessed foodstuff is filled in a packing film formed with a multiplicity of minuscule current passing apertures and heated by passing a current therethrough to ripen and sterilize same, to thereby provide a packed processed food with a high degree of efficiency.
Still another object is to provide an apparatus for producing a packed food, in which an electrode plate having a salt solution impregnated electrical contact member placed thereon is located at an open bottom of an insulating container which is open at the top; unprocessed foodstuff is filled in the insulating container in such a manner that a sheet of packing film in a developed condition is interposed between the salt solution impregnated electrical contact member with minuscule current passing apertures of the packing film being positioned between the unprocessed foodstuff and the electrical contact member; and an electrode plate is brought into pressing contact with the top of the unprocessed foodstuff in the packing film through a salt solution impregnated electrical contact member. Then a current is passed uniformly between the two electrode plates, to produce in a short period of time a packed food ripened and sterilized by the heat generated by the current passed therethrough.
Additional and other objects, features and advantages of the invention will become apparent from the description set forth hereinafter when considered in conjunction with the accompanying drawings, in which: